Afin d’apporter les soins adéquats aux victimes d'arrêt cardiaque extrahospitalier, l'évaluation de leur état hémodynamique est primordiale. La prise de pouls manuelle ne permet pas une identification fiable de l'arrêt cardiaque par les profanes ou une discrimination des rythmes organisés par les premiers intervenants. Dans ce contexte, l'entreprise Schiller Médical a cherché à intégrer dans sa gamme de défibrillateurs un module de détection de l'hémodynamique systémique par analyse de l'électrocardiogramme et des variations d'impédance transthoracique recueillis via les électrodes de défibrillation. Ce travail de recherche mené en partenariat entre l'entreprise Schiller Médical et l'Institut Pluridisciplinaire Hubert Curien de l’Université de Strasbourg a consisté dans un premier temps a recherché, lors d'arrêt cardiaque induit électriquement chez l'homme, des descripteurs des variations d'impédance transthoracique marqueurs de l’hémodynamique systémique. L’identification des descripteurs les plus pertinents a par la suite permis de construire des modèles prédictifs des défaillances circulatoires. Nous avons mis en lumière des limites à l’utilisation des variations d’impédance transthoracique. Elles sont prises en considération pour la documentation des interventions extrahospitalières destinée à l’apprentissage des algorithmes de classification des rythmes perfusants et rythmes sans pouls. / Providing suitable emergency care during out of hospital cardiac arrest requires the diagnostic of the circulatory status. Manual pulse check does not provide a reliable way for laypersons to identify cardiac arrest or for first responders to discriminate organized rhythms. Thus, Schiller Medical sought to embed an hemodynamic sensor in its external defibrillators by analyzing the electrocardiogram and transthoracic impedance recorded via the defibrillation pads. This thesis work stemmed from a partnership between Schiller Medical and the Institut Pluridisciplinaire Hubert Curien of the Université de Strasbourg. We first identified transthoracic impedance featureslinked with the circulatory status by studying clinically induced cardiac arrest. The most relevant features were later selected to form predictive models of hemodynamic collapse. We uncovered restrictions to the use of transthoracic impedance. We took them into account for the annotation of out of hospital cardiac arrests aimed at training algorithms for the classification of pulseless electrical activity and pulsatile rhythms.

Introdução: Apesar do desenvolvimento tecnológico, permanece baixa a sobrevida hospitalar das vítimas de parada cardiorrespiratória extra-hospitalar. Há importante dúvida na literatura quanto à retenção de habilidades de ressuscitação cardiopulmonar (RCP) e a periodicidade adequada de treinamento para manutenção dessas habilidades. O presente estudo investigou a retenção, em alunos a partir de treinamento no primeiro semestre de ingresso no curso médico, das habilidades práticas de RCP até 42 meses após o referido treinamento. Métodos: Estudo de corte transversal, realizado com 298 alunos de graduação de uma faculdade de Medicina, treinados com base nas diretrizes de ressuscitação de 2010 da American Heart Association. Foram avaliados 205 alunos sem retreinamento das habilidades, divididos em quatro grupos conforme o tempo decorrido desde o treinamento de ingresso: 73 alunos após 1 mês, 55 após 18 meses, 41 após 30 meses e 36 após 42 meses. A análise da retenção das habilidades foi comparada com 93 alunos que referiram ter realizado retreinamento em RCP. Dezenove habilidades de RCP e nove potenciais erros de técnica na execução das ventilações pulmonares e compressões torácicas foram avaliados por meio de simulação realística e revisados com utilização de filmagem e avaliadores independentes. Resultados: A média de retenção das dezenove habilidades nos alunos sem retreinamento foi: 90% após 1 mês, 74% após 18 meses, 62% após 30 meses e 61% após 42 meses (p < 0,001). Nos alunos que referiram retreinamento, a retenção foi de 74% após 18 meses, 70% após 30 meses e 66% após 42 meses do treinamento inicial. Realizada curva de predição da retenção de habilidades, com estimativa de 80% das habilidades mantidas após 10 meses, 70% após 21 meses e 60% após 42 meses. A profundidade das compressões torácicas foi a habilidade com maior retenção ao longo do tempo (87,8%), sem diferença estatística entre os quatro grupos. Houve aumento da prevalência de compressões realizadas com menos de 5 cm de profundidade quando realizadas em frequência maior que 120 por minuto. A média da frequência de compressões torácicas obtidas nos grupos após 1, 18, 30 e 42 meses foi, respectivamente, 114, 114, 104 e 108 compressões por minuto; 104 (50,7%) alunos mantiveram frequência média entre 100-120 por minuto. As ventilações pulmonares apresentaram diminuição progressiva de retenção, de 93% após 1 mês até 19% após 42 meses (p < 0,001). Todos os alunos efetivaram o choque com o desfibrilador externo automático, porém com o grupo após 1 mês do treinamento com menor tempo para efetivação do choque e maior prevalência de posicionamento adequado das pás do desfibrilador. Conclusões: O presente estudo demonstrou diferentes níveis de retenção para as habilidades de RCP e diferentes níveis de decréscimo de tais habilidades ao longo de 42 meses. A profundidade das compressões torácicas e o uso do desfibrilador externo automático foram as habilidades com maior retenção ao longo do tempo. Treinamentos adicionais ao longo do curso de Medicina atenuaram a perda de habilidades, mas sem retorno ao desempenho observado após 1 mês do treinamento. Sugerimos que o intervalo mínimo de retreinamento para manutenção de pelo menos 70% das habilidades deva ser de 18 a 24 meses / Introduction: Despite technological development, the survival of victims of out-ofhospital cardiac arrest remains low. There are important questions in the literature regarding the retention of cardiopulmonary resuscitation (CPR) skills and the ideal frequency of retraining required to enhance retention of skills. This study investigated the retention of practical CPR skills by medical students over 42 months after training in the first semester of admission to the medical course. Methods: A cross-sectional study was conducted with 298 undergraduate medical students who were trained based on the 2010 American Heart Association resuscitation guidelines. A total of 205 students divided into four groups according to the time elapsed since the entrance training were evaluated without retraining (73 students after 1 month, 55 students after 18 months, 41 students after 30 months and 36 students after 42 months). The analysis of the retention of skills was compared to 93 students who reported having performed retraining in CPR. Nineteen CPR skills and nine potential technical errors in ventilations and chest compressions were evaluated by realistic simulation and reviewed using filming by independent examiners. Results: The mean retention of the nineteen skills in not retrained students was: 90% after 1 month, 74% after 18 months, 62% after 30 months and 61% after 42 months (p < 0.001). In retraining students, retention was 74% after 18 months, 70% after 30 months, and 66% after 42 months of initial training, with statistical difference between the students with and without retraining in the 30-month group (p=0.005). The estimation of mean skill retention was 80% after 10 months, 70% after 21 months and 60% after 42 months. The depth of chest compressions was the skill with greater retention over time (87.8%), with no statistical difference among groups. There was an increase in the prevalence of compressions performed with less than 5 cm depth when performed at a frequency greater than 120 per minute. The mean chest compressions rate obtained in the groups after 1, 18, 30 and 42 months were 114, 114, 104 and 108 per minute, respectively, and 104 (50.7%) students maintained a mean frequency of 100-120 per minute. Pulmonary ventilation showed a progressive decrease in retention from 93% after 1 month to 19% after 42 months (p < 0.001). All students delivered the shock with the automated external defibrillator; however, for the group one month post-training, the time for the application of the shock was lower, and the prevalence of adequate positioning of the defibrillator pads was greater. Conclusion: This study showed different retention levels for CPR skills and different decrease levels of these skills over 42 months. Depth of chest compressions and use of automated external defibrillator were the skills with the highest retention over time. Additional training throughout the medical course attenuated the loss of skills, but no return to the initial performance achieved after 1 month. We suggest that the minimum retraining interval for maintenance of at least 70% of skills should be 18 to 24 months

La directive européenne 2013/35/UE précise les exigences minimales pour la protection des travailleurs exposés aux champs électromagnétiques et définit les porteurs d’implants comme travailleurs à risques particuliers. Concernant les porteurs de défibrillateur automatique implantable (DAI) ou de stimulateur cardiaque (SC), l’exposition au champ électrique ou magnétique d’extrêmement basse fréquence crée des inductions à l'intérieur du corps humain pouvant générer une tension perturbatrice susceptible de causer le dysfonctionnement de l’implant. Le sujet de ce travail de thèse porte sur la compatibilité électromagnétique des implants cardiaques soumis à un champ électrique basses fréquences (50/60 Hz). Des simulations numériques ont été effectuées afin de concevoir un banc expérimental pour l’exposition de fantômes incluant des stimulateurs ou des défibrillateurs implantables. Une étude expérimentale a permis d’établir par provocation les seuils de champ électrique permettant d’éviter tout dysfonctionnement éventuel de l’implant. Dans la partie simulation numérique ; un modèle humain virtuel (fantôme numérique contenant un implant cardiaque) a été placé en position debout sous une exposition verticale à un champ électrique. La méthode des éléments finis a été utilisée pour définir les phénomènes induits au niveau de l’implant cardiaque avec une résolution de 2mm (logiciel CST®). Dans la partie expérimentale, un banc d'essai dimensionné pour permettre de générer un champ électrique pouvant atteindre 100 kV/m aux fréquences 50-60 Hz a été conçu, optimisé et réalisé afin d’analyser le comportement des implants cardiaques. Plusieurs configurations ont été étudiées. Sur 54 implants cardiaques actifs testés (43 stimulateurs et 11 défibrillateurs) à des niveaux de champs électriques très élevés (100 kV/m) générés par notre dispositif expérimental, aux fréquences de 50-60 Hz, aucune défaillance n’a été observée pour des niveaux d’exposition publics et pour la plupart des configurations (+99%) sauf pour six stimulateurs cardiaques dans le cas d’une configuration « pire cas » peu réaliste en clinique : mode unipolaire avec une sensibilité maximale et en détection auriculaire. Les implants configurés avec une sensibilité nominale en mode bipolaire résistent bien à des champs électriques dépassant les valeurs seuils telles que définies par 2013/UE/35. / The European Directive 2013/ 35 / EU specify minimum requirements for the protection of workers exposed to electromagnetic fields and define with implants as “workers at particular risk”. Regarding the implantable cardioverter defibrillator wearers (ICD) or pacemaker (PM), exposure to electric or magnetic field of extremely low frequency creates inductions inside the human body that generate interference voltage which may cause the dysfunction of the implant. This thesis investigates the electromagnetic compatibility of cardiac implants subjected to an electric field low frequency (50/60 Hz). Computational simulations are effectuated in order to design an experimental bench for the exposure of a phantom including pacemakers or implantable defibrillators. A provocative study is established to define the electric field thresholds for preventing any malfunction of the implant. In numerical simulations; a virtual human model (digital phantom containing a cardiac implant) was placed in an upright position in a vertical exposure to an electric field. The finite element method was used to define the inductions in the cardiac implant level with a resolution of 2 mm (CST® software). In the experimental part, a test bench designed to allow generating an electric field up to 100 kV / m at frequencies 50-60 Hz was constructed, optimized and employed to investigate the behavior of cardiac implants.Several configurations were studied. 54 active cardiac implants (43 pacemakers and 11 defibrillators) are submitted to very high electric field of 50-60 Hz (up to 100 kV / m) inside the experimental bench. No failure was observed for public exposure levels for most configurations (+ 99%) except for six pacemakers in the case of a configuration clinically almost inexistent: unipolar mode with maximum sensitivity and atrial sensing.The implants configured with a nominal sensitivity in bipolar mode are resistant to electric fields exceeding the low action levels (ALs), even for the most high ALs, as defined by 2013 / 35 / EU

Le taux de mortalité chez les patients à risque d’arythmies cardiaques menaçantes à la vie a été considérablement réduit grâce au défibrillateur cardiaque implantable (DCI). Toutefois, des préoccupations uniques face au DCI, y compris les chocs que l’appareil peut déclencher, sont susceptibles de provoquer des symptômes d'anxiété et une limitation perçue des activités chez les porteurs de DCI. Ces réactions émotives et modifications de comportement peuvent affecter l’acceptation du patient envers le DCI. Cette étude pilote randomisée avec groupe contrôle (n=15 /groupe) visait à examiner la faisabilité et l'acceptabilité d'une intervention infirmière individualisée de même que ses effets préliminaires sur l’anxiété, le fonctionnement dans les activités de la vie quotidienne et l’acceptation du DCI auprès de nouveaux porteurs de DCI. L'intervention infirmière, basée sur la théorie du Human Caring et teintée d’une approche cognitive comportementale, ciblait les préoccupations individuelles face au DCI. À partir des préoccupations identifiées, l’infirmière intervenait en mettant l'accent sur les croyances contraignantes du patient, qui pouvaient mener à de l’anxiété et des comportements d'évitement. Après randomisation, les patients du groupe intervention (GI) ont participé à un premier entretien en face-à-face avant le congé hospitalier. Subséquemment, deux entretiens se sont faits par téléphone, à environ 7 et 14 jours suite au congé hospitalier. Les résultats soutiennent la faisabilité et l’acceptabilité du devis de l’étude et de l’intervention évaluée. De plus, ils soulignent le potentiel de l’intervention à diminuer les sentiments anxieux chez les participants du GI. Les résultats de cette étude pilote offrent des pistes de recherches futures et permettront de guider la pratique clinique. / Patients with an implantable cardiac defibrillator (ICD) decrease their risk of mortality related to life threatening arrhythmias. However, multiple concerns about this device exist, including ICD shocks, which may result in increased anxiety and a perceived limitation in performing everyday activities. These emotional reactions and behavioral changes may have a negative impact on the acceptance of the device. The purpose of this randomized pilot study with a group control (n=15 / group), was to verify the feasibility and acceptability of an individualized nursing intervention aiming to decrease anxiety, improve performance in everyday activities and device acceptance in patients with newly implanted ICDs. Based on Human Caring theory and a cognitive behavioral approach, this intervention addressed each patient’s unique concerns. From the identified concerns, the nurse intervened focussing on the patient’s dysfunctional beliefs that can lead to anxiety and avoidance behavior. After randomization, the first encounter for the experimental group (EG) was face-to-face before hospital discharge. Subsequently, two encounters were made via telephone, 7 and 14 days after discharge. The results support the feasibility and acceptability of the study design and the intervention evaluated. In addition, they emphasize the potential of the intervention to reduce symptoms of anxiety among the participants of the EG. The results of this pilot study may provide directions for future research and help guide clinical practice.

The theme for this thesis is based on the European Resuscitation Council's guidelines for cardiopulmonary resuscitation of 2015. One of the important points of these procedures is the use of an automatic external defibrillator (AED). These devices were developed for informed responders without the knowledge of cardiac rhythm diagnostics and allow to perform an early defibrillation of the heart, before the arrival of emergency services. AED is a sophisticated device that is a part of the equipment of I - firefighters and policemen. Training of these so-called first aid responders performs the local emergency service team. Over the years 2015 and 2016, the majority of the professionally active firefighters and police officers in one selected Czech district who have the automatic external defibrillator in their equipment attended a training in how to use this device. The aim of this thesis is to determine whether the concept of the training courses is sufficient. If the theoretical part is well understandable for the respondents, and whether the practical training is sufficient - not only the actual compressions and ventilation, but also the use of an automatic external defibrillator, or whether it would be appropriate to extend this training. In this research I used a quantitative method - an...

Introdução: Apesar do desenvolvimento tecnológico, permanece baixa a sobrevida hospitalar das vítimas de parada cardiorrespiratória extra-hospitalar. Há importante dúvida na literatura quanto à retenção de habilidades de ressuscitação cardiopulmonar (RCP) e a periodicidade adequada de treinamento para manutenção dessas habilidades. O presente estudo investigou a retenção, em alunos a partir de treinamento no primeiro semestre de ingresso no curso médico, das habilidades práticas de RCP até 42 meses após o referido treinamento. Métodos: Estudo de corte transversal, realizado com 298 alunos de graduação de uma faculdade de Medicina, treinados com base nas diretrizes de ressuscitação de 2010 da American Heart Association. Foram avaliados 205 alunos sem retreinamento das habilidades, divididos em quatro grupos conforme o tempo decorrido desde o treinamento de ingresso: 73 alunos após 1 mês, 55 após 18 meses, 41 após 30 meses e 36 após 42 meses. A análise da retenção das habilidades foi comparada com 93 alunos que referiram ter realizado retreinamento em RCP. Dezenove habilidades de RCP e nove potenciais erros de técnica na execução das ventilações pulmonares e compressões torácicas foram avaliados por meio de simulação realística e revisados com utilização de filmagem e avaliadores independentes. Resultados: A média de retenção das dezenove habilidades nos alunos sem retreinamento foi: 90% após 1 mês, 74% após 18 meses, 62% após 30 meses e 61% após 42 meses (p < 0,001). Nos alunos que referiram retreinamento, a retenção foi de 74% após 18 meses, 70% após 30 meses e 66% após 42 meses do treinamento inicial. Realizada curva de predição da retenção de habilidades, com estimativa de 80% das habilidades mantidas após 10 meses, 70% após 21 meses e 60% após 42 meses. A profundidade das compressões torácicas foi a habilidade com maior retenção ao longo do tempo (87,8%), sem diferença estatística entre os quatro grupos. Houve aumento da prevalência de compressões realizadas com menos de 5 cm de profundidade quando realizadas em frequência maior que 120 por minuto. A média da frequência de compressões torácicas obtidas nos grupos após 1, 18, 30 e 42 meses foi, respectivamente, 114, 114, 104 e 108 compressões por minuto; 104 (50,7%) alunos mantiveram frequência média entre 100-120 por minuto. As ventilações pulmonares apresentaram diminuição progressiva de retenção, de 93% após 1 mês até 19% após 42 meses (p < 0,001). Todos os alunos efetivaram o choque com o desfibrilador externo automático, porém com o grupo após 1 mês do treinamento com menor tempo para efetivação do choque e maior prevalência de posicionamento adequado das pás do desfibrilador. Conclusões: O presente estudo demonstrou diferentes níveis de retenção para as habilidades de RCP e diferentes níveis de decréscimo de tais habilidades ao longo de 42 meses. A profundidade das compressões torácicas e o uso do desfibrilador externo automático foram as habilidades com maior retenção ao longo do tempo. Treinamentos adicionais ao longo do curso de Medicina atenuaram a perda de habilidades, mas sem retorno ao desempenho observado após 1 mês do treinamento. Sugerimos que o intervalo mínimo de retreinamento para manutenção de pelo menos 70% das habilidades deva ser de 18 a 24 meses / Introduction: Despite technological development, the survival of victims of out-ofhospital cardiac arrest remains low. There are important questions in the literature regarding the retention of cardiopulmonary resuscitation (CPR) skills and the ideal frequency of retraining required to enhance retention of skills. This study investigated the retention of practical CPR skills by medical students over 42 months after training in the first semester of admission to the medical course. Methods: A cross-sectional study was conducted with 298 undergraduate medical students who were trained based on the 2010 American Heart Association resuscitation guidelines. A total of 205 students divided into four groups according to the time elapsed since the entrance training were evaluated without retraining (73 students after 1 month, 55 students after 18 months, 41 students after 30 months and 36 students after 42 months). The analysis of the retention of skills was compared to 93 students who reported having performed retraining in CPR. Nineteen CPR skills and nine potential technical errors in ventilations and chest compressions were evaluated by realistic simulation and reviewed using filming by independent examiners. Results: The mean retention of the nineteen skills in not retrained students was: 90% after 1 month, 74% after 18 months, 62% after 30 months and 61% after 42 months (p < 0.001). In retraining students, retention was 74% after 18 months, 70% after 30 months, and 66% after 42 months of initial training, with statistical difference between the students with and without retraining in the 30-month group (p=0.005). The estimation of mean skill retention was 80% after 10 months, 70% after 21 months and 60% after 42 months. The depth of chest compressions was the skill with greater retention over time (87.8%), with no statistical difference among groups. There was an increase in the prevalence of compressions performed with less than 5 cm depth when performed at a frequency greater than 120 per minute. The mean chest compressions rate obtained in the groups after 1, 18, 30 and 42 months were 114, 114, 104 and 108 per minute, respectively, and 104 (50.7%) students maintained a mean frequency of 100-120 per minute. Pulmonary ventilation showed a progressive decrease in retention from 93% after 1 month to 19% after 42 months (p < 0.001). All students delivered the shock with the automated external defibrillator; however, for the group one month post-training, the time for the application of the shock was lower, and the prevalence of adequate positioning of the defibrillator pads was greater. Conclusion: This study showed different retention levels for CPR skills and different decrease levels of these skills over 42 months. Depth of chest compressions and use of automated external defibrillator were the skills with the highest retention over time. Additional training throughout the medical course attenuated the loss of skills, but no return to the initial performance achieved after 1 month. We suggest that the minimum retraining interval for maintenance of at least 70% of skills should be 18 to 24 months

Abstrakt Bakgrund: Användning av i implanterbar kardioverter-defibrillator (ICD) och pacemaker ökar i samhället då fler överlever hjärtkomplikationer. Många av dessa patienter överlever genom att patienten har fått en pacemaker eller ICD implanterad. Samtidigt som implanterbar kardioverter-defibrillator ökar så ökar även MR-undersökningarna i samhället. MR - modaliteten är en undersökning som inte ger patienter joniserande strålning samt ger denna modalitet bättre bildkvalité på människans mjukvävnader till jämförelse med en DTundersökning. MR - undersökningarna har blivit en populär metod att diagnostisera patienter och även patienter med pacemaker eller ICD. Trots detta har externa magnetfältet påverkat pacemakern och ICD till den grad att patienter har avlidit. Syftet: Syfte med studien är att belysa befintlig kunskap om säkerhetsrutiner och risker vid MR-undersökningar av patienter som har pacemaker eller implanterbar kardioverter-defibrillator. Metod: Studien genomfördes som en allmän litteraturöversikt. Artikelsökningar gjordes i databaserna Pubmed och Cinahl. Tolv kvantitativa artiklar valdes som sedan granskades och analyserades för att svara mot syftet. Resultat: Säkerhetsrutiner och risker kring pacemaker och ICD sammanställdes i två huvudkategorier vilka är säkerhetsrutiner och risker. Slutsats: I röntgensjuksköterskans yrkesroll är det viktigt att följa det lokala säkerhetsrutiner såsom att följa sjukhusets protokoll och att ha bra kommunikation med patienter med pacemaker eller ICD för att följa upp så patienten inte får några symtom under eller efter undersökningen. Genom att följa dessa säkerhetsrutiner förebygger vårdpersonalen symtom hos patienter och riskerna minimeras. / Abstract Introduction: The use of implanted cardiovascular devices such as pacemaker and ICD is increasing in society as more people survive cardiac complications. Many of these patients survive by having a pacemaker or ICD implant. While implanted cardiovascular devices are increasing, so are MRI scans in society. MRI is an examination that does not give patients ionizing radiation and provides better image quality of human soft tissues compared to CT scan. MRI scans have become a popular method of diagnosing patients and also patients with pacemaker or ICD. Despite this the external magnetic field affects the pacemaker and ICD to the point where patients have died. Aim:The purpose of the study is to shed light on existing knowledge about safety routines and risks in MRI examinations of patients who have a pacemaker or implantable cardioverter-defibrillator. Method: The study was conducted as a general literature overview. Article searches were made in the Pubmed and Cinahl databases. Twelve quantitative articles were selected which were then reviewed and analysed to meet the purpose. Results: Safety routines and risks around pacemaker and ICD were compiled into two main categories, which are safety routines and risks. Conclusion: In the professional role of the radiographer, it is important to follow local safety procedures such as following hospital protocols, monitoring and also having good communication with patients who have pacemaker or ICD during and after examinations so the patient does not experience any symptoms. By following these safety procedures the healthcare professionals will minimize the risks and symptoms in patients with cardiovascular implantable during and after MRI scan.

The work deals with implantable devices and possibilities of interference of elektromagnetic field. At first, the electromagnetic compatibility is discussed. Basic terms are explained, followed by insisting on resources of possible distrurbing of implantable devices and standards dealing with this issue. Furthermore, short chapter about devices affecting function of implantable devices is introduced. It means devices which patients with implantable devices may meet in common life, as well as devices used in common life, also devices used jn medical environment. In the next part, measuring process of electromamagnetic effect in working compartment of FN Brno magnetotheraphy and elektrotheraphy is devised. There is a concept of measuring card thanks to which impulses of implantable devices are measured. Finally, a description of measuring on implantable devices in FN Brno. MIKULA, D. EMD instruments and electromagnetic immunity. Brno, 2009. 74 s. Master’s thesis in Brno University of technology on faculty of elektrical engeenerig and communication. Supervisor Ing. Marie Havlíková , Ph.D.

Introduction : La cardiopathie arythmogène du ventricule droit (CAVD) est une pathologie d’origine génétique se traduisant par un remplacement cicatriciel qui affecte de façon prédominante le ventricule droit (VD). Le diagnostic est complexe car il repose sur un ensemble de critères cliniques plutôt que sur un seul test diagnostic. L’atteinte du VD se traduit de façon prédominante par des arythmies ventriculaires qui peuvent parfois conduire à la complication la plus redoutée de cette affection : la mort subite. La prédiction et la prévention de celle-ci sont des enjeux cruciaux de la prise en charge de cette maladie. Objectifs : Ce travail vise à améliorer la prise en charge des patients atteints de CAVD de deux façons distinctes. Premièrement, en tentant de faciliter le diagnostic par la validation des critères diagnostiques en vigueur. Deuxièmement, en améliorant la stratification du risque d’arythmie ventriculaires soutenues et plus spécifiquement celui de la mort subite et des arythmies potentiellement mortelles (tachycardie ventriculaire > 250 bpm, fibrillation ventriculaire) en créant des modèles de prédiction du risque permettant de déterminer le risque individuel de chaque patient. Résultats : Article 1 - Un total de 407 patients consécutifs référés pour une résonnance magnétique cardiaque pour suspicion de CAVD ont été inclus. De ceux-ci, 66 (16%) ont reçu un diagnostic définitif selon le critère de référence établi pour cette étude: le consensus d’un panel d’experts. Globalement, les critères performent bien avec une sensibilité et spécificité à 92%. Cependant, certains critères tels l’ECG haute amplitude (SAECG) et certains critères reliés à l’histoire familiale ne sont pas discriminants. Le retrait de ces critères pourrait réduire le nombre de faux positifs sans pour autant augmenter le nombre de faux négatifs (net reclassification improvement de 4,3%, p=0,019). De plus, la combinaison des critères électrocardiographiques et de la présence d’arythmies ventriculaires a une sensibilité de 100%, ce qui peut faciliter dans certains cas le dépistage en limitant la nécessité de recourir à l’imagerie. Pour les articles 2 et 3, une base de données incluant des patients avec un diagnostic définitif de CAVD a été assemblée à partir de bases de données provenant de six pays (Canada, États-Unis, Pays-Bas, Suède, Norvège, Suisse). Article 2 - Un total de 528 patients sans histoire antérieure d’arythmies ventriculaires soutenues a été inclus pour développer un modèle de prédiction de risque. De ceux-ci, 146 (27,7%) ont subi un événement arythmique durant un suivi médian de 4,8 ans. Des huit prédicteurs initialement identifiés (âge inférieur au diagnostic, sexe masculin, syncope cardiaque récente, nombre de dérivations avec des inversions des ondes T, fardeau d’extrasystoles ventriculaires (ESV) en 24h, tachycardie ventriculaire non-soutenue et fractions d’éjection des ventricules gauche et droit), sept ont été retenus dans le modèle, excluant seulement la fraction d’éjection du ventricule gauche (FEVG). Le modèle peut distinguer adéquatement entre les patients avec et sans événement (C-index de 0,77) avec un optimisme minimal (courbe de calibration de 0,93). L’utilisation de cet algorithme permettrait de réduire l’utilisation de défibrillateurs implantables de 20% par rapport à l’algorithme du consensus le plus largement utilisé. Article 3 - Une cohorte de 864 patients incluant à la fois ceux avec et sans histoire antérieure d’arythmie ventriculaire soutenue a été assemblée. Durant un suivi médian de 5,75 ans, 93 patients ont eu un épisode d’arythmie rapide selon la définition préalablement établie. Des huit facteurs de risque cités ci-haut, seulement quatre ont été retenus dans le modèle : l’âge plus jeune au diagnostic, sexe masculin, fardeau d’ESV en 24h et nombre de dérivations avec des inversions des ondes T. Fait à noter, les événements antérieurs ne se sont pas avérés prédicteurs d’arythmies potentiellement mortelles subséquentes. Le modèle peut distinguer adéquatement entre les patients avec et sans événement (C-index de 0,74) et présente un optimisme minimal avec une courbe de calibration de 0,95. Conclusion : Bien que les critères diagnostiques en vigueur pour la CAVD aient une performance adéquate, ceux-ci peuvent être simplifiés et améliorés par le retrait de certains de ces critères. L’absence de critères électrocardiographiques combinés et d’arythmies ventriculaires peut exclure une CAVD, ce qui peut en simplifier le dépistage. Chez les patients atteints de CAVD, la prédiction du risque et la sélection des patients pour l’implantation d’un défibrillateur peuvent être facilités grâce à deux modèles complémentaires de prédiction du risque permettant de prédire les événements arythmiques soutenus dans le premier et plus spécifiquement les arythmies ventriculaires potentiellement mortelles dans le deuxième. Ces outils sont particulièrement utiles dans une approche de prise de décision partagée. / Introduction: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic pathology resulting in a fibro-fatty replacement predominantly affecting the right ventricle. The diagnosis is complex and is based on a set of clinical criteria. Involvement of the right ventricle predominantly results in ventricular arrhythmias which constitutes the most common presentation but can also lead to the most feared consequence: sudden cardiac death. Predicting and preventing this catastrophic outcome are crucial in the management of this disease. Objectives: This work aims to improve the management of patients with ARVC in two distinct ways. First, by attempting to facilitate the diagnosis by validating the currently used diagnostic criteria. Second by improving risk stratification for sustained ventricular arrhythmias and specifically life-threatening ventricular arrhythmias (LTVA defined as ventricular tachycardia > 250 bpm, ventricular fibrillation, and sudden death) by creating risk prediction models to derive individual risk. Results: Manuscript 1: a total of 407 patients referred for cardiac magnetic resonance for suspected ARVC were consecutively enrolled. Of these, 66 (16%) received a definitive diagnosis of ARVC by the determined endpoint: the consensus of an expert panel. Overall, the criteria performed well with a sensitivity and specificity of 92%. However, certain criteria such as the signal averaged electrocardiogram (SAECG) and certain criteria related to family history failed to discriminate. Removing these criteria could reduce false positives without increasing false negatives (net reclassification improvement of 4.3%, P = 0.019). In addition, the electrocardiographic criteria and the presence of arrhythmia had a sensitivity of 100%, which can facilitate screening in some cases by making imaging optional. For manuscripts 2 and 3, a cohort including patients with a definitive diagnosis of ARVC was assembled from databases in 6 countries (Canada, United States, Netherlands, Sweden, Norway, Switzerland). Manuscript 2: a total of 528 patients with no previous history of sustained ventricular arrhythmias were included to develop a risk prediction model. Of these, 146 (27.7%) had an arrhythmic event during a median follow-up of 4.8 years. Of the eight predictors initially identified (younger age at diagnosis, male sex, recent cardiac syncope, the number of leads with T wave inversions on the ECG, burden of extrasystoles in 24 hours, non-sustained ventricular tachycardia and left and right ventricular ejection fraction), seven were retained in the model, excluding only left ventricular ejection fraction. The model adequately distinguished between patients with and without an arrhythmic event (C-index of 0.77) with minimal optimism (calibration slope of 0.93). Using this prediction model would reduce the use of defibrillators by 20% compared with the most commonly used consensus based on a risk factor approach. Manuscript 3: a cohort including both patients with and without a prior history of ventricular arrhythmia of 864 patients was assembled. During a follow-up of 5.75 years, 93 patients had an LTVA as defined above. Of the 8 risk factors cited above, only 4 were retained in the model: younger age at diagnosis, male sex, burden of extrasystoles in 24 hours and number of leads with T-wave inversions. Importantly, previous events are not predictive of these subsequent life-threatening arrhythmias. The model adequately distinguished between patients with and without an event (C-index of 0.74) with minimal optimism (calibration slope of 0.95). Conclusion: Although the current diagnostic criteria for ARVC perform adequately, they can be simplified and improved by removing underperforming individual criteria. The absence of any ECG criteria and ventricular arrhythmias may rule out ARVC, which may simplify screening. In patients with ARVC, risk prediction and patient selection for a defibrillator can be facilitated by two complementary risk prediction models for sustained arrhythmic events or more specifically for LTVA. These tools are particularly useful in a shared decision-making approach for implantable cardioverter defibrillator implantation.

Les nouvelles technologies médicales contribuent aux dépenses en santé qui ne cessent de croître, alors que les budgets se trouvent limités. L’évaluation économique des technologies devraient permettre d’identifier quelles sont celles qui sont les plus rentables. Malgré cela, plusieurs technologies dont le rapport coût-efficacité reste plutôt limite ou défavorable sont utilisées en médecine moderne et remboursées par notre système public de santé. Ce mémoire se concentre sur deux technologies en santé cardiovasculaire dont le rapport coût-efficacité est plutôt limite mais qui sont fréquemment utilisées au Canada; les tuteurs médicamentés ou pharmaco-actifs et les défibrillateurs cardiaques implantables (DCI). Nous avons fait une évaluation contingente de ces technologies dans le but d’examiner si ce type d’évaluation économique complémentaire pouvait procurer un point de vue nouveau sur la valeur économique et sociétaire des ces technologies. Les résultats de ces deux évaluations indiquent que les patients accordent une grande importance aux bénéfices que procurent ces deux technologies. Nos résultats soutiennent les politiques de santé actuelles de rembourser de façon libérale ces deux technologies. / Technological innovations have greatly contributed to the rising costs in healthcare, while budgets have remained limited. Economic evaluations of technologies should identify which technologies are cost-effective. However, several technologies used in modern medicine are either borderline cost-effective or even not cost-effective according to many studies. This thesis focuses on two technologies in cardiovascular medicine which are considered borderline cost-effective; drug-eluting stents and implantable cardioverter defibrillators. We conducted a contingent valuation of these technologies in hopes of determining if this alternative type of economic evaluation could give a novel point of view on the economic and societal value of these technologies. Results indicated that patients greatly valued benefits provided by these two technologies. Our result support our public healthcare system policies’ of liberal reimbursement of these two technologies.